Analysis of energy and exergy of lavender extract powder in spray dryer

In recent years, the research in the field of medicinal plants as therapeutic supplements has increased significantly. Lavender extract is widely used among medicinal plant products due to its unique therapeutic properties. Since drying processes require high energy, this study was conducted to study the performance of the spray dryer in the production of lavender extract powder at three levels of air temperature 150°C, 180°C, and 210°C, three levels of compressed air flow rate 6, 8, and 10 L/min and ratios of maltodextrin-drying aid to the mass of dry matter of the extract 0%, 25%, and 50% by response surface method. For this purpose, the energy efficiency and exergy of the powder production process were examined. According to the obtained results, increasing the inlet air temperature and the inlet air flow rate increased the energy efficiency and exergy and decreased the energy efficiency and exergy, respectively. The energy efficiency of the drying process varied in the range of 6.55%–15.87%, and the exergy efficiency (${\eta }_{ex}$) of the drying process in the range of 2.87%–5.84%. Also, the ${\eta }_{ex}$ of the spray dryer was calculated in the range of 20.05%–38.78%. Based on the energy efficiency and exergy, the optimal production of lavender plant extract powder was obtained at the air temperature of 210°C, the compressed air flow rate of 6 L/min, and the amount of drying aid of 11.9 g/L.